Liquefied gas expander



July 10, 1945. R nousgm 2,379,953 LI ugFmn GAS EXPANDER I Filed Nov; 16, 1942i I z-shms-smy 2- Fla-3 INVENTOR I on. oousuN BYE/,2 2

A V EYS Patented July 10, 1945 UNITED STATE LIQUEFIED GAS EXPANDER Donald R. Douslin, Bartlesville, Okla., assignor to Phillips Petroleum Co Delaware mpany, a corporation of Application November 16, 1943, Serial No. 510,522 16 Claims. (01;. 2o2. 1s0) This invention relates in general to automatic pressure control of an analytical fractionating apparatus. This, invention is particularly applicable, although not necessarily restricted, to

the analysis of hydrocarbon gases and liquids or mixtures of hydrocarbon gases and liquids such as natural gas; natural gasoline, gasoline and other petroleum distillates. or in fact any mixture of materials which is capable of analysis by distillation under conditions of low temperatures and pressures and especially where the pressure within the fractionating column must be very carefully I controlled. The invention relates in particular to the distribution ofcooling agent in the condenser section of the column whereby said pressure is controlled. In some respects, the present invention is an improvement on the patent to W. J. Podbielniak No. 1,967,258, issued July 24, 1934. The arrangement described by Podbielniak includes a control device which is adapted to maintain a constant pressure in the column. A manometer which is connected with the vapor-outlet tube by. a side arm is provided with electrodes leading to an electrical circuit which includes a solenoid valve. The valve controls the eflective' pressure applied from a source of constant air pressure to a body of liquid air in a flask. In the operation of the Podbielniak arrangement, pressure increase in the fractionating-cclumn is registered on the mercurycolumn of'the manometer, closing the circuit through the solenoid valve and applying pressure to the liquid air which is forced into the cooling section of the column. thereby reducing the fractionation pressure. The range of pressure change is too broad for. accuracy in fractionation of twoliquids with close boiling points. and varying vapor-pressures. My invention is a manifest improvement over the arrangement of the patent in providing fully automatic control of the fra'ctionating pressure in an advantageous and expedient manner and with the elimination of electrical circuits, sole.- nold valves and other relatively expensive equipment which have heretofore been-considered essential to the operation of such devices.- My

application, Serial No. 468,148, filed December 7.

the other apparatus of Figs. 1 and.

has been found to give a more uniform pressure in the fractionating column than the Podbielniak patent apparatus, it has been observed that liquefied gases being used as cooling agentswill wet the inside of the-dispensing tube 5 if the tube becomes colder than a certain definite temperature and it will in the fractionation of certain lighter hydrocarbons. When the dispensing tube is wet by the liquefied gas, the liquefied gas will accumulate at the bottom of the tube and drop at undesired times onto the distilling tube ,and cause undesired cooling. The effect is harmful to the operation of the pressure control and cooling agent feed device and to the maintenance of a constant pressure. The control of pressure cannot be too accurate, .as-the principal object is to attain the greatest possible degree of accuracy.

The principal object 01 the invention v is'to maintain the pressure in the distilling tube atas constant a pressure as is possible.

Another object is to prevent undesired cooling through the dropping of liquid cooling agent directly on the tube, and to conduct excess cooling agent away from the tubeto expand without adversely atlecting the operation of the pressure control device. 1

. An important object is to provide 'a mermaifly wheel which will act to average and smooth out temperature changes.

Another object is to provide means for sud ous path.

While the apparatus of Serial Number 488,148

Another object is to provide automatic feed of cooling agent in combination with the thermal "fly wheel so that constant pressure is malnr tained.

Other objects are to accomplish the desired relooking at the accompanying drawings. u I

In the drawings:

Fig. 1 is an elevaticnal view of the fractionating-column, constant pressure control and automatic feed with the liquid gas expander in the cooling zone of the column. l

Fis. 2 is an elevational view'in cross section of meter stick ll.

2 the floating heedle valve'and closely related parts with the other parts brolren away.

Fig. 3 is an elevational view in cross section of and closely related parts, with parts broken away. I

Fig. 4 is a perspective view of'theexpander. 'With specific reference to Figure 1, l is an the cooling zone of the column, the gas expander The outlet tube l for the spent gases is provided leading out from chamber 23 through cover plate 20 to the atmosphere. A packing 3| is generally provided to form a bottom limit to the cooling zone 3, sealing around distilling tube ll.

In operation, heat is applied to the bottom of I the fractionating column and overhead vapors analytical fractionating column of the general variation in the fractionating column in a manner hereinafter described. The overhead vapors from the fractionating process pass through conduit 8 to an accumulator not shown. Conduit I is provided with a side arm 8 which connects with a mercury manometer it fixed to the The arm A of the manometer connects with conduit 7 and is provided with a floating needle valve designated generally at I! clearly shown in Figure 2, arm MA is vented to the atmosphere through air vent II and has an elongated relatively restricted section ll through which the head I! of the needle valve will barely pass. The needle valve may be formedof any pass through the line 8 to the accumulator, not shown. The pressure variation in the fractionating column is registered on the manometer column fluid which cause the needle valve to rise and .fall relative to the restricted portion ll. The

quantity ofair under constant pressure from air line ll passing head 15 to the vent I3, and likewise the pressure, imposed ontheliquid air supply I, is therefore, a function of the pressure f in the fractionating column. It is therefore obvious that increase of pressure in the fractionating column will force an increased quantity of liquid air into the cooling zone 3 reducing the 7 pressure in the column. During normal operationv and while the pressure in the column is constant a small quantity of liquid air is .continuousiy forced into the cooling zone. Byregulation of the compressed air pressure admitted 1 at "and by adiusting the mercury level with in Figure 1 and shown in detail in Figure 2. As

suitable material either solid or hollow according to the specific gravity of the manometer fluid, the main prerequisite being that it floats on the body of fluid in the column. In the present application I prefer to construct the needle valve of solid glass with an enlarged lower portion for contact with the manometer fluid. A constriction I6 is provided in the arm MA to limit the downward movement of the needle valve. This the levelingbottle II it is possible to fractionate under any desired constant pressure automatically and'without attention of the operator. I

If the pressure rises suddenly intube ii for any reason the liquid gas will gush out of tube 5 across lip 25 and directly contact tube ii to rapidly bring down the temperature. If the pressure rise is slow however, the liquid gas will flow.

out of the lower portion of bell 21 and will not cross the lip butjwill flow down 26 and the outside of expander II. The expander 2. acts as a reservoir onthermal fly wheel" and absorbs the shock of the cooling agent, butbeing a good conductor'draws heat out of the tube Ii. Any

. dripping on 28 is also absorbed without shock to the magnitude of which is dependent on the position of the needle valve II. A leveling bottle it having a pinch clamp is is connected'with the manometer tube I! at the bend thereof.

m'lligure 3a liquid zas expander 20 is shown in cooling zone 3. While the expander could rest directly on the glass I prefer to mount it on spaced cork supports 2|, three in number al-' though more or less may be employed. The expander is made preferably of aluminum or copper, which have high specific heats and high' thermal conductivity. but of course other mateerally preferable because they are generally the best heat conductors and reservoirs.

, The expander has a central bore 2! which may be enlarged at 23 if desired. The exact shape of, these bores and of the exterior of the expander is not so important, a slot 24 is cut from' borel! to the exterior of the expander, and the {downwardly rials maybe employed, although metals are genthe system.

The position of outlet tube 4 is such that all gases in cooling zone 3 must pass close to tube ll inside the expander 20 on their way out. This insures proper controlled cooling of tube Ii. The space between tube Ii and bore 22 allows evaporation of the cooling liquid when it is forced in quantity over lip 25 whenfast cooling is neceagann Besides providing a good surface for the expansion of liquefied gas, the expander 20 also acts as a good conductor and reservoir for the absorption of heat; these characteristics of the ex,-

pander make it a good device for maintaining a ing will be doneb'y vaporization of the liquid cooling agent on the distilling tube 'CI, but with heavier hydrocarbons most of thecoling will be by heat transfer through the cold expander itself. Through the operation of the control equipment described above all cooling will be such that the pressure in tube I I is substantially constant at all times. f

While only one embodiment of my invention has been illustrated, it is obvious that many changes may be made without departing from the spirit of my invention-the scope of whic is set forth in the following claims.

Having described my invention, I claim: 1. In a fractional distilling apparatus the combination comprising a source of fluid under a constant pressure, a first conduit connectin said source and a supply of cooling liquid, a distilling column, a metal expander for cooling the upper portion of the column, a second conduit conducting cooling liquid from the supply to the metal'expander in response to said pressure, a

bleed valve in said first conduit for varying the pressure therein, means to deflect the cooling liquid directly against the distilling column during relatively large rates of' flow thereof and to deflect the cooling liquid away from the distilling column during relativel slow rates oi flow thereof.

2. In a fractional distilling apparatus the combination comprising a sourceof fluid under constant pressure. a first conduit connecting said source and a supply of'cooling liquid, a distilling column, a metal expander for cooling the upper -a U tube communicating at one end with the distilling column and at the other end with said first conduit, a heavy liquid inthe lower part of the U tube responsive to the pressures in the first conduit and the distilling column through the respective ends of the U tube, said bleed valve including a valve head floating in said heavy entering the chamber and having a belied end disposed adjacent the lip whereby cooling liquid is discharged across the lip onto the. distilling tube during rapid ilow of said liquid, and is discharged down the sloping surface during slow flow of said liquid, and an outlet conduit leading from a portion oi the central bore below said lip to the exterior of the chamber.

I 5. A cooling liquid dispenser for a distillationcolumn comprising in combination, a distilling tube, ,a chamber around the tube forming a cooling zone, a liquid gas expander in the. cooling 'zonecomprisingametalbodmthebodyhaving a central bore receiving the distilling tube and a slot leading to the upper portion of the central bore, a lip formed in the body in the slot, a downwardly sloping surface on the body in the slot exterior of'the lip, an inlet conduit entering the chamber and having abelled end disposed adjacent the lip whereby cooling liquid is discharged across the lip onto the distilling tube during rapid flow of said liquid, and is discharged down the sloping surface during slow flow of said liquid, and an outlet conduit leading from a portion of the central bore below said lip to the exterior of the c 6. A cooling liquid dispenser for a distillation columncomprising in combination, a distilling tube, a chamber around the tube forming a cooling zone, aliquid gas expander in 'the cooling zcne comprising a metal body having a relatively liquid, whereby the amount of cooling liquid reaching said metal expander is varied so as to keep said pressure in said distilling column substantially constant.

3. A cooling liquid dispenser for a distillation column comprising in combination, a distilling tube, a chamber around the tube forming a cooling zone, a liquid gas expander in the cooling zone comprising a metal body having a relatively high specific heat and relatively high heat capacity, the body having a central bore receiving the distilling tube and a slot leading to the upper portion of the central bore, a lip formed in the body in the slot, a downwardly sloping surface on the body in the slot exterior of the iii), an inlet conduit entering the chamber and having a belied end disposed adjacent the lip whereby cooling liquid is discharged across the lip onto the distillingtube during rapid ilow of said liquid, and

i is dischargeddown the sloping surface durin slow flow of said liquid, and an outlet conduit leading from a portionof the central bore. below said lip to the exterior of the chamber.

4. A cooling liquid dispenser for a distillation column comprising in combination, a distilling tube, a chamber around thetube forming a, coolterior of the chamber.

high specific heat and relatively high heat capenalty, the bodyhaving a central bore receiving the distilling tube and a slot leading to the upper portion of the central bore, a lip formed in the body'in the slot, a downwardly sloping surface onthe body in the slotexterior of the lip, an inlet conduit entering the chamber disposedadjacent the lip whereby cooling liquid is discharged across the lip onto thel distilling tube duringrapid flow 'of said liquid, n is discharged down .the sloping surface during slow flow of said liquid, and an outlet conduit leading from a portion of the central bore below 7. A cooling liquid dispenser foradistillation column comprising in combination, a distilling tube, a chamber around the tube forming a coola ing zone, aPliquid gas expander in the cooling zone comprising a metal body having a relatively high specific heat and relatively high heat capacity, the body aving a central bore receiving the distilling tu e and a slot leading to the upper portion of the central bore, a lip formed in the body in the slot, a downwardly sloping surface on the body in the slot exterior ofithe lip, an inlet-conduit entering the'chamber and having a belled end disposed adjacent the lip whereby cooling liquid-is discharged across the lip onto the distilling tube during rapid flow of said liquid, and is discharged down the sloping surface during slow flow of said liquid, and an outlet conduit leading to the exterior of the chamber. 7

as cooling liquid dispenser for a distillation column comprising in combinations distilling tube. a chamber around the tube forming a cooling zone, a liquid gas expander in the cooling zone comprising a body having a relatively high speciflc heat and relatively high heat capacity, the 4 body having a central bore receiving the distilling tube and a slot leading to the upper portion of thecentral bore, a lip .torined in the bodyin the ing-zone. a liquid gas expander in the cooling zone comprising a body having a relatively high specific heat and relatively high he t. capac y, the body having a central bore receiving the distilling tube'and a slot leading to the upper portion of the central bore. .a lip formed in the slot, a downwardly sloping surface on the body ody in the slot, a downwardlysloping surface in the slot exterior of the lip, an inlet conduit on the body in the slot exterior of the lip, an

said lip to the exinlet conduit entering the chamber disposed adjacent the lip whereby cooling liquid is discharged across the lip onto the distilling tube during rapid flow of said liquid, and is discharged down the sloping surface during slow flow of said liqasraots 1 ratus, a distillationtuhe having" a heating zone uid, and an outlet conduit leading below said lip to the exterior of the chamber.

9. A cooling liquid dispenser for a distillation column comprising in combination a distilling tube, a chamber around the tube forming acooling zone, a liquid gas expander in the cooling zone comprising a body, the body having a cen-' tral bore-receiving'the distilling tube and a slot leading to the upper portion of the central bore,

a lip formed in'the body in the slot, a downwardly sloping surface on the body in the slot exterior of the lip, an inlet conduit entering the chamber and having a belied end disposed adjacent the lip whereby cooling liquid is discharged across .the li onto the distilling tube during rapid flow of-said liquid, and is discharged down the sloping surface during slow flow of said liquid, and an outlet conduit leading to the exterior of the chamber..

10. A cooling liquid dispenser for a distillation" column comprising in combination, a distilling tube,-a chamber around the tube forming a cooling zone, a liquid gas expander in the cooling zone comprising a metal body, the body having a central bore receiving the-distilling tube and a slot leading to the upper portion of the central bore, a lip formed in thebody in the slot. a

downwardly sloping surface on the body in the slot exterior of the lip, an inlet conduit entering the chamber disposed adjacent'the lip whereby cooling liquid is discharged across the lip onto the distilling tube during rapid flow of said liquid, and is discharged down the sloping surface during slow.flow of said liquid, and an .outlet conduit leading to the exterior of the chamber.

11. A cooiingliquidsdispenser for a distillation column comprising in'combination, a distilling tube, a chamber around the tubeforming a cooling zone, a liquid gas expander in the cooling z'one comprising a the body having a central bore receiving the distilling tube and a slot leading to theupper portion of the central bore; a lip formed in the :body in the slot, a downwardly sloping surface on the body "in the slot exterior of the lip, an inlet conduit entering the chamber disposed adand a cooling zone for operation at a desired pres-' sure, heat reservoir means in the cooling zone, a

ing a body-having a heat conductivity substantially higher than that of glass and a substantial heat capacity, said body having a bore there-" through for receiving said tube therethrough, said body having a slot therein in one side-and entering the upper part of said bore at a point below the top of said body for receiving said stream of liquefied gas, said slot being disposed to deflect. e

a large stream of said liquefied gas'to the upperpart of said bore, a lip for deflecting said liquefied gas formed in the body in the slot and a down-.

wardly sloping surface .on the body in the 'slot exterior oitne up, said surface of said body form=-= ing an evaporating surface for a small stmuiun'of- .said liquefied gas.

15. A liquid gas expander for use in heat ex change between a stream of liquefied gas capable of rapid evaporation and a vertical tube, com-'- prising a body havinga bore therethrough for.

receiving said' tube therethrougmsaid body hav-=' ing aslot therein in one" side and entering the" upper part of said bore at a pointbelow the top of said body for receiving said stream of lique fled gas, said slot being disposed to deflect a large stream of said liquefied gas to the upper part of said bore, a lip for deflecting said liquefied Bass formed in the body in the slot and a downwardly sloping surface on the body in the slot exterior of. the lip, said surface of said body forming an evap crating surface for a small stream of said liquefied:

gas. a 16. A liquid gas expander for use in heater-- change between a stream of liqueiiedgas capable;

' of rapid evaporation anda. vertical tube, compris jacent the lip whereby cooling liquid is discharged across them). bntothe distilling tube during'rapid flow of said liquid,- and "is discharged down the sloping surface during'slow flow ofsaid'liquid, and

Y an outlet conduit leading to the exterior of thechamber. 7 12. In a constant pressure distillation apparatus, a distillation tube having a heating zone and a cooling zone, heat reservoir means in the' cooling. zone, and means responsiveto small in--'.

creases in pressureinthe'distilling tube to supply acooling agentto the heat reservoir and responsive to larger increases in pressure to supply the cooling agent directlyto the distillation tube.

13. In a constant pressure distillation appaing a body having a bore therethrough for loosely receiving said vertical tube ,therethrough, the lower portion of said bore being enlarged to pro-1 .vide a chamber for expansion of said gas-upon:

evaporation, a conduitpassing through said and connecting said enlarged portion of said bore with the atmosphere, said body having a slot; thereinflto receive said stream of liquefledgam'as lip for deflecting said liquefied gas formed in the bodyin the slot and disposed to deflect a large stream of said liquefled'gas into said bore and a.

downwardly sloping surface onthe body inthe.

slot exterior of the lipfor-evaporating a small stream of saidliquefied gas.

nomm a. nous arsa 

